What A Robot Found 1.5 Miles Under The South Atlantic

Summary

A remotely operated vehicle (ROV) gave scientists their first live view of the seabed in a submarine canyon off Argentina. The canyon lies about 300 km from Mar del Plata and reaches depths of more than 3.5 km. The expedition revealed rich deep-sea life—and rubbish scattered from roughly 1,100 m down to the deepest areas surveyed.

Discoveries and observations

• Scientists documented 29 pieces of marine litter. Twenty-seven were plastic, including packaging, cups, fishing line, rope, and cables. One wrapper was recorded at 3,814 m.
• A rubber boot was a striking find. The subtitles give different depths for it: it was photographed at 2,598 m and later described as recovered from 2,047 m.
• The litter was found in clusters. Researchers say submarine canyons can funnel debris, concentrate it, and trap it. In the largest concentration surveyed, the team counted fewer than three items per kilometre—less than figures cited for some canyons elsewhere.
• Fishing gear among the debris, including lines and a cord with a hook, suggests that fishing vessels are a likely source. The team noted that other sources are possible; labels on the rubbish did not point to a single origin.
• Some animals were living on the debris. Footage showed an ophiura on a plastic container, worms on fishing line, small arthropods on decaying plastic, and a coral relative called a polyp attached to nylon line. Researchers suggest that partly buried or snagged litter can provide stable surfaces for organisms to settle on.
• The ROV also filmed coral reefs, red mushroom coral, squid, lobsters, and an octopus guarding eggs. A bright-orange starfish that drew attention for resembling a SpongeBob SquarePants character was not a new species.

New species and taxonomy

• Specimens collected by the expedition were examined at a workshop in Buenos Aires by 20 taxonomists and early-career researchers. They confirmed 57 species new to science and five new genera.
• The new species included 20 copepods, 22 sea cucumbers and crinoids, 14 corals and sea feathers, and one mollusk with a fang-shaped shell.
• A horn-like sea cucumber was named Loki. It was one of 10 new sea-cucumber species found in the canyon.
• Some coral specimens may represent two new genera and possibly a new family, but genetic testing is still needed.
• The researchers examined only about a tenth of the collected copepod samples. Every copepod they assessed was new to science, so the full number of new species among the remaining samples is unknown.

Survey approach and significance

• The ROV SuBastian filmed the canyon floor. Scientists reviewed 240 hours of footage and recorded detected litter.
• The team mapped the locations of the debris and examined collected specimens. Earlier work in 2012 and 2013 had relied on nets and trawls rather than live seabed footage.
• The litter survey establishes a baseline for comparison with future dives. It also documents how human debris can persist at great depths and provide surfaces for animals to inhabit.

Researchers and sources featured

Researchers

• Daniel Loreta (also rendered “Loretta” in the subtitles)
• Martin Brøgger
• Francisco Alonso Solís Marín
• Mariano Martínez
• The taxonomists and early-career researchers at the Buenos Aires workshop

Sources and institutions

• NOAA
• Ocean Census database
• Schmidt Ocean Institute
• Argentina’s national collections, including the Natural History Museum in Buenos Aires